The long-term goal of this research program is to develop an optical magnetometer array for use in fetal magnetocardiography (fMCG) and fetal magneto-encephalography (fMEG) systems. The proposed magnetometer, based on recent advances in magnetometer technology, represents the first viable alternative to SQUID magnetometers; thus, the potential impact of the research on the field of biomagnetism is enormous. Utilization of fMCG and fMEG has been limited by the high cost of acquisition and maintenance associated with SQUID technology. The atomic magnetometer can mitigate these disadvantages while maintaining or even surpassing the magnetic field sensitivity of SQUID magnetometers. A novel, four-channel atomic biomagnetometer array was recently demonstrated for adult and fetal MCG studies. The next steps are to refine it for use in conventional magnetically shielded rooms and to extend its capabilities to inexpensive shielding geometries. The specific aims of this project are: 1. to demonstrate a 9-channel atomic magnetometer array for direct comparison to commercial SQUIDs for detection of signals from 20 week gestation period fetuses. 2. To extend the bandwidth and dynamic range of the atomic magnetometer for use in inexpensive shielding environments. 3. To make pre-clinical studies of at-risk fetuses with the magnetometer array. To achieve these aims, the researchers will investigate new modes of operation of the magnetometer that improve its bandwidth and dynamic range. New data processing methodologies will be considered, and the developments will be tested with human subjects.